Control of Histamine Formation by Morganilla morganii in Synthetic Media and Mackerel Fish Homogenate Using Blue Green Alga, Spirulina platensis
text
article
2014
eng
Histamine, a chemical health hazard, is formed from the amino acid histidine by bacterial histidine decarboxylase.The effect of Spirulina platensis alga extracts on the population of Morganella morganii and histamine formationwere studied. Among many solvents, diethyl ether extract gave the best inhibition even at the lowest concentration(1000 ppm) using disc diffusion method. Concentrations of 50-1000 ppm of algal extract were tested against Morganellamorganii in histidine decarboxylase broth (HDB). Significant reduction in the population was noticed at allthe tested concentrations notably at the highest one (1.7 log units). Around 50% reduction in histamine content wasobtained at the concentration of 500 and 1000 ppm algal extract. The highest reduction (>2.5 log units) in M. morganiicount in stored sterilized and raw mackerel (incubated for 48 hrs at 25°C) was noticed at 1000 and 2000 ppm of algalextract. The dose 2000 ppm significantly controlled histamine formation (>60%) in stored mackerel. These resultsopen new horizons to control histamine formation at a large scale of fish industry.
Alexandria Journal of Food Science and Technology
The Scientific Society of Food Industries, Alexandria, Egypt.
1687-3920
11
v.
1
no.
2014
1
10
https://ajfs.journals.ekb.eg/article_20237_81eade3c6068e71bc4e0b4ce92a4cf9f.pdf
dx.doi.org/10.12816/0025345
Chemical Composition of Okra Seeds and Some Physico-Chemical Characteristics of Extracted Oil
text
article
2014
eng
Okra (Abelmochus esculentus L.) seeds were analyzed and characterized in terms of physical properties, chemicalcomposition, mineral content and some oil characteristics. Seeds were found to be a good source of crude oil andprotein being 15.20% and 24.32% on dry weight basis, respectively. The seeds possessed high content of crude fiberand could be considered as a good source of K, Na, Mg and Ca. The extracted oil was slightly high in saponificationvalue and relatively low in iodine value, so it could be classified as a semi – dry oil. In addition, the crude oil showedlow peroxide and acid values indicating its high stability against deterioration. Total lipid fractions of okra seed oilconsist mainly of nine classes in which triacylglycerols being the major class. Palmitic, oleic and linoleic acids werethe major fatty acids and constituted about 90.71% of the total fatty acids.
Alexandria Journal of Food Science and Technology
The Scientific Society of Food Industries, Alexandria, Egypt.
1687-3920
11
v.
1
no.
2014
11
19
https://ajfs.journals.ekb.eg/article_20249_a997cd5bde60a35c78b78e7535f7e3d4.pdf
dx.doi.org/10.12816/0025346
Effect of Pretreatments on Controlling Enzymatic Browning Before Drying of Eggplant Slices
text
article
2014
eng
The present study was carried out to investigate polyphenoloxidase inhibition in eggplant slices before drying.Pretreatments were carried out single or combined from immersion in ascorbic acid, citric acid or sodium chloridesolutions at different concentrations 0.5, 1.0, 1.5, 2.0% and /or steaming for 2,4,6,8 min. Polyphenoloxidase activityof fresh eggplant slices was 0.65 unit /g/min. Sever inhibition was detected with increasing chemical inhibitors concentrationor steam regardless of chemical inhibitors types .The inhibitory effect of steam pretreatments or variouschemicals inhibitors on eggplant slices was found to decrease in the following order steam treatment > ascorbic acid >sodium chloride > citric acid at the same concentration level. Combination of chemical inhibitors and steam treatment(Ascorbic acid, citric acid, sodium chloride at levels 0.5% and steam treatment for 2min) as hurdle technology resultedmost effective inhibition on enzymatic browning. Dried eggplant slices with aforementioned combined pretreatmentat low concentration of chemical inhibitors and steam were less three times of enzymatic browning index than controltreatment (without pretreatment). Also, inhibition of polyphenoloxidase of eggplant slices before drying were highermaintained bioactive compounds especially phenolic compounds, ascorbic acid and antioxidant activity than control
Alexandria Journal of Food Science and Technology
The Scientific Society of Food Industries, Alexandria, Egypt.
1687-3920
11
v.
1
no.
2014
21
29
https://ajfs.journals.ekb.eg/article_20250_347ec2ab70cfb2f9896dbfe852b1a195.pdf
dx.doi.org/10.12816/0025347
Methods for Determining the Antioxidant Activity: A Review
text
article
2014
eng
Antioxidants are considered as important bioactive compounds on account of many health benefits along withtheir pivotal role in delaying oxidative rancidity of numerous foods. Consequently, the requirement of a standard assayis very important in order to compare the results of different laboratories and validation of the conclusion. This reviewarticle explains the scientific basis of numerous different methods for determining antioxidant activity. Advantagesand disadvantages of these methods have been taken into consideration along with either the mechanism or the modeof action for each. Comparative assessment using different antioxidant evaluation methods strongly suggests that notall the adopted methods are highly related and thereby antioxidant capacity should be evaluated by more than onemethod. Moreover, application of antioxidant assays in food analysis have been also reviewed briefly.
Alexandria Journal of Food Science and Technology
The Scientific Society of Food Industries, Alexandria, Egypt.
1687-3920
11
v.
1
no.
2014
31
42
https://ajfs.journals.ekb.eg/article_20251_46bd1a0433e6dc694aa7953b19fd1868.pdf
dx.doi.org/10.12816/0025348
Optimizing The Extraction Conditions of Gelatin Obtained from Chicken Processing By-Products
text
article
2014
eng
Chicken by-products are not often processed into high-value products. One important application is the productionof high quality chicken gelatin to meet the needs of markets that are not amenable to beef gelatin. So, thepresent study deals with the production of gelatin from chicken skin, feet and bone. The extraction process of gelatinfrom chicken by-products was optimized through the use of alkali (NaOH) and its effects on the protein yields andthe physicochemical properties of the produced gelatin were investigated. As soaking period proceeded as yield decreased.The optimum sodium hydroxide concentration and liming period for gelatin production of chicken tissueswere defined as 2.5 % for 60 hr. Yield of gelatin of chicken skin, feet and bone reached to the maximum at 60°C and6hr extraction time. Skin, feet and bone gelatins had similar amino acid composition, with a total imino acid content ofabout (12.92– 16.99%). Amino acid contents of chicken tissue gelatins were different from that of commercial gelatindue to the diversity in terms of raw materials and production process.
Alexandria Journal of Food Science and Technology
The Scientific Society of Food Industries, Alexandria, Egypt.
1687-3920
11
v.
1
no.
2014
43
52
https://ajfs.journals.ekb.eg/article_20253_4ddd077a9e351b953b0bcde5397f7a8b.pdf
dx.doi.org/10.12816/0025349
Production and Evaluation of Low Fat Cake Containing Flaxseed and Okra gums as a Fat Replacer
text
article
2014
eng
Fat was replaced in cakes with flaxseed and okra gums at 25 up to 100%. The results indicated that the proximatechemical composition of the replacement cakes showed a significant increase (P≤0.05) in moisture as the replacementlevels of both gums increased relative to a significant lowered in fat content. The caloric value of replaced cakes withboth gums showed a significant lowered which was more pronounced in flaxseed replacement cakes rather than okragum cakes being 21.11 and 19.33% at 100% replacement, respectively. Replacement with both gums at different levelssignificantly lowered the weight, volume, height and specific volume of cakes. Okra gum-replaced cakes exhibitedbetter physical properties than flaxseed-replaced cakes. The texture profile analysis (TPA) showed that both gumsadded tenderness and resilience to the cakes up to 75% and 100% replacement which was more pronounced in okragum-replaced cakes rather than those replaced with flaxseed. The sensory evaluation of cakes showed that the colourand flavour of okra gum-replaced cakes were highly acceptable up to 100% replacement level, where, the texture andoverall acceptance were accepted by the panelists up to 75%. Flaxseed gum-replaced cakes were highly accepted upto 75% replacement levels. Both gums used in the present study were very successful in producing highly acceptabletender cakes thus allowing production of potentially healthier food items.
Alexandria Journal of Food Science and Technology
The Scientific Society of Food Industries, Alexandria, Egypt.
1687-3920
11
v.
1
no.
2014
53
60
https://ajfs.journals.ekb.eg/article_20255_d5be39311e1496d1b73d6e5d0210b94a.pdf
dx.doi.org/10.12816/0025350
Manufacturing of White Cheese-Like Product Using Flaxseed Oil and Skim Milk
text
article
2014
eng
Milk fat has been considered as a hypercholesterolemic agent because it contains cholesterol and a generous proportion of saturatedlong-chain fatty acids. A nutritionally balanced product has led to the development of a choice fat source which has a criticalimpact on the fatty acid profile. The fortification of food with essential polyunsaturated fatty acids (PUFA), such as omega-3, is an interestingand timely topic. The health benefits associated with PUFA ingestion are several. Flaxseed oil which is rich in nutraceuticalsomega-3 fatty acid has been reported to be a beneficial substitute for milk fat in some dairy products. However, a complete pilot scaleresearch is essential to evaluate the cheese sensory properties as well as the fatty acids stability of flaxseed oil upon long-term storage.Hence, this study aimed to determine the composition and acceptability of flaxseed oil formulated reduced fat cheese with optimumlevels of milk fat substituted by flaxseed oil. The control made from whole milk and two types of white cheese-like products weremade from skim milk and a mixture of skim milk with flaxseed oil. Samples were subjected to (moisture, T.S, fat, protein, lactose, salt,ash, acidity (%) and pH value ) and sensory evaluation in addition to microbiological content tests (total counts and coliform groups)at zero, 15, 30 and 45 days. Incorporation of flaxseed oil into cheese showed clear change in the chemical composition comparing withthe control and cheese that made from skim milk except in fat content which was lower than in the control without no change in flavourand texture. However, it increased slightly the colour of cheese into yellowish and had no effect on total counts and coliform counts.Flaxseed oil incorporation also gave compatible overall acceptability as compared to the control, therefore, fortification of cheese withflaxseed oil seems ideal and consumers may enjoy the health benefits of omega-3 fatty acids with reduced-fat cheese
Alexandria Journal of Food Science and Technology
The Scientific Society of Food Industries, Alexandria, Egypt.
1687-3920
11
v.
1
no.
2014
61
69
https://ajfs.journals.ekb.eg/article_20256_3e9df573e5b74e91411cee8280544ebb.pdf
dx.doi.org/10.12816/0025351